At 9:30 this morning, the principal of the Ron Brown Academy in Brooklyn stood in her school’s auditorium, watching a fight break out.

Across from her, a tall girl in a tight pink shirt slapped at the girl in front of her. Three other girls grabbed the tall one’s arms and kicked at her legs. The girls broke apart as two boys doing cartwheels chased them off stage.

The principal, Celeste Douglas, broke into applause. She was watching the teenagers — who had grins plastered to their faces, and whose fight moves had been carefully choreographed by their teachers — perform their winter dance routine.

“Music makes me feel free,” said Justin, one of the dancers, after the performance. He is a seventh grader at Ron Brown, a middle school in Bedford-Stuyvesant.

Music has also provided the school with an opportunity to improve its test scores, boost attendance and jump off the state’s watch list.